Typically, a rotary machine with a rotor (rotating shaft) such as a gas turbine is provided with a thrust bearing device that receives thrust load (force acting in the axial direction) of the rotor.
In recent years, as the output of gas turbines has increased, the thrust load borne by a thrust bearing device has also increased. For example, Patent Document 1 describes a device for reducing the thrust load of a rotor that is provided with a piston on an end portion of a rotor, the piston moving in an axial direction via oil pressure.